The primary objective of these studiesis to evaluate the influence of ascorbic acid on the pharmacokinetics of antipyrine and caffeine in a vitamin C-deficient elderly population sample. The first portion of the study will involve the evaluation of the physical and nutritional status of twenty male geriatric subjects with specific reference to their plasma and leukocyte ascorbate levels prior to, during, and following ascorbate supplementation. The protocol for this study involves the administration of one of the test drugs (i.e., antipyrine or caffeine) which will be studied separately, the collection of blood, and the assessment of oxidative hepatic metabolic capabilities utilizing the measurement of pharmacokinetic parameters (e.g., half-life (t1/2) and total body clearance (TBC). The half-life and total body clearance of each drug will be assessed at various levels of supplemental ascorbate intake (ranging from O to 250 mg per day) at weekly intervals over a ten week period. Simultaneous assessment of plasma and leukocyte ascorbic acid levels will be obtained, and the correlation between vitamin C nutrition (i.e., supplementary dose and plasma and leukocyte levels) and oxidative metabolic capabilities (i.e., t 1/2 and TBC) will be determined. Finally, the influence of ascorbic acid supplementation on metabolic and excretory processes will be differentiated by allowing the plasma level of ascorbate to return to pre-supplement levels (i.e., presupplement excretory patterns) and administering the test drug while tissue saturation is still high (i.e., elevated metabolic patterns). It is anticipated that data derived from this collaborative interdisciplinary investigation will demonstrate the influence of vitamin C on the oxidative hepatic metabolism of antipyrine and caffeine in an elderly population sample. This information will make a significant contribution to the body of knowledge needed to clarify the complex interrelationships between nutrition, metabolism, and pharmacokinetics in the elderly.